Re: [PATCH V1] accel/amdxdna: Fix potential NULL pointer access in amdxdna_gem_vmap()

[Lizhi Hou <lizhi.hou@amd.com>]

On 7/7/26 10:29, Max Zhen wrote:
>
>
> On 7/7/2026 Tue 10:23, Lizhi Hou wrote:
>> If the heap BO was never vmapped before its handle was closed and the
>> user then vmaps the dev BO (which triggers amdxdna_gem_vmap(heap_bo)),
>> and drm_gem_vmap fails — NULL pointer dereference at abo->client->xdna.
>>
>> Fix it by get xdna pointer through to_xdna_dev(to_gobj(abo)->dev).
>>
>> Fixes: d76856beb4a4 ("accel/amdxdna: Refactor GEM BO handling and add 
>> helper APIs for address retrieval")
>> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
> Reviewed-by: Max Zhen <max.zhen@amd.com>

Thanks a lot for reviewing the patch. Sashiko bot reports other places 
which can trigger abo->client NULL pointer dereference. I will create a 
V2 patch which fix those places as well.

Lizhi

>> ---
>>   drivers/accel/amdxdna/amdxdna_gem.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/accel/amdxdna/amdxdna_gem.c 
>> b/drivers/accel/amdxdna/amdxdna_gem.c
>> index 64c7d82713b0..5033a0e5c6ab 100644
>> --- a/drivers/accel/amdxdna/amdxdna_gem.c
>> +++ b/drivers/accel/amdxdna/amdxdna_gem.c
>> @@ -198,6 +198,7 @@ amdxdna_gem_destroy_obj(struct amdxdna_gem_obj *abo)
>>    */
>>   void *amdxdna_gem_vmap(struct amdxdna_gem_obj *abo)
>>   {
>> +    struct amdxdna_dev *xdna = to_xdna_dev(to_gobj(abo)->dev);
>>       struct iosys_map map = IOSYS_MAP_INIT_VADDR(NULL);
>>       int ret;
>>   @@ -210,7 +211,7 @@ void *amdxdna_gem_vmap(struct amdxdna_gem_obj 
>> *abo)
>>       if (!abo->mem.kva) {
>>           ret = drm_gem_vmap(to_gobj(abo), &map);
>>           if (ret)
>> -            XDNA_ERR(abo->client->xdna, "Vmap bo failed, ret %d", ret);
>> +            XDNA_ERR(xdna, "Vmap bo failed, ret %d", ret);
>>           else
>>               abo->mem.kva = map.vaddr;
>>       }
>